Drift Mechanism and Gain Stabilization of Digital Closed-Loop Quartz Flexible Accelerometer in Start-Up Performance

Zhao

et al. 2023

Meas. Sci. Technol.

The distributed capacitance inside the quartz flexible accelerometer (QFA) coupled the high frequency voltage excitation signal in the differential capacitance detection circuit to the torquer coil, and superimposes the torquer driving current to form the driving noise. In this study, the values of the distributed capacitance inside the QFA were simulated. According to the formation mechanism of the QFA driving noise, the equivalent circuit model of the driving noise is established, and the driving noise characteristics of the detection circuit with single excitation and double excitation source are analysed. The theoretical and experimental results show that the electric field coupled driving noise transmission system is a first-order system with high-pass characteristics. The driving noise of the single excitation detection circuit is larger than that of the dual excitation detection circuit, and the dual excitation detection circuit can reduce the driving noise by 39.77% when the QFA shell is grounded. The equivalent acceleration of the electric field coupled driving noise is between tens of μg to hundreds of mg, which is one of the important noise sources that affect the measurement accuracy of the QFA. A measure was proposed to suppress the high-frequency driving noise by adding a low-pass filter after the sampling output of the driving current, which can reduce the driving noise to 1.85 μg and effectively reduce the influence of the driving noise on the measurement accuracy of the QFA.

Section: Working Principle Of the Closed-loop System Of Qfamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on driving noise of quartz flexible accelerometer torquer

Zhao

et al. 2023

Meas. Sci. Technol.

“…The impact of this noise on the performance of the accelerometer cannot be ignored. In recent years, there have been many studies on the effect of noise caused by temperature change on the performance of accelerometers [ 7 , 8 , 9 , 10 , 11 ]. The newly researched temperature compensation method maintains the stability of the cold start output at about 30 μg [ 12 ], and increases the stability of 1 g acceleration output to 14.6 μg [ 13 ], which significantly improves the temperature stability of the QFA.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Noise-Detection Characteristics of Electric Field Coupling in Quartz Flexible Accelerometer

Zhao

et al. 2023

Micromachines

The internal electric field coupling noise of a quartz flexible accelerometer (QFA) restricts the improvement of the measurement accuracy of the accelerometer. In this paper, the internal electric field coupling mechanism of a QFA is studied, an electric field coupling detection noise model of the accelerometer is established, the distributed capacitance among the components of the QFA is simulated, the structure of the detection noise transfer system of different carrier modulation differential capacitance detection circuits is analyzed, and the influence of each transfer chain on the detection noise is discussed. The simulation results of electric field coupling detection noise show that the average value of detection noise can reach 41.7 μg, which is close to the effective resolution of the QFA, 50 μg. This confirms that electric field coupling detection noise is a non-negligible factor affecting the measurement accuracy of the accelerometer. A method of adding a high-pass filter to the front of the phase-shifting circuit is presented to suppress the noise of electric field coupling detection. This method attenuates the average value of the detected noise by about 78 dB, and reduces the average value of the detected noise to less than 0.1 μg, which provides a new approach and direction for effectively breaking through the performance of the QFA.

“…The other type is the digital close-loop QFA, which owns higher theoretical accuracy compared with the analogue type [10]. The studies about the digital QFA principally concentrate on the digital servo circuit design, close-loop parameters estimation, and capacitance detection [13][14][15]. Ran et al [13] introduced the works on the analysation of the entire close-loop model and estimation of the loop-parameter-drifting.…”

Section: Introductionmentioning

confidence: 99%

Mechanical model analysis and reliability design approach of Quartz Flexible Accelerometer under fractured state

Xiao

IET Circuits, Devices & Syst

Song

et al. 2023

Self Cite

Currently, the Quartz Flexible Accelerometer (QFA) mounted for the applications working in high acceleration environment are suffering from the fracture of the flexible beams under external acceleration shock. This paper presents the mechanical model and reliability design approach of QFA to maintain the measuring ability under a fractured state. The structural parameters changed significantly in the mechanical model under a fractured state compared to those in the original model. A modified structure to maintain the measuring ability of QFA under a fractured state is designed with the reference of the sensitive module in Electrostatic Suspended Accelerometer (ESA). The corresponding close‐loop system is corrected and discretised to ensure the stability requirements of the mechanical model. A static experiment is conducted to prove the effectiveness of the proposed model by a prototype QFA with completely fractured flexible beams. The result shows helpful on the preliminary research for QFA with the similar sensitive structure to ESA.